assistant and treating patients. His trial is under way. And in opening statements, his lawyer said the hospital is to blame. Abc's john schriffen has that story. Why did you do this? Reporter: Matthew scheidt was either an overeager teen, interested in medicine. Individuals did not believe he was a p.A. Reporter: Or he was a skilled con man, playing doctor. Dressed in the scrubs, the stethoscope around the neck. Even at the terminology. ♪ Come fly with me ♪ Reporter: Like a scene from the movie "catch me if you can." I'm a doctor. Reporter: The 18-year-old florida man is on trial this morning, accused of masqueradiing as a physician assistant in this osceola hospital. Performing cpr on a patient who was overdosing. When he was arrested last september, he talked openly to police about what happened. That's when he said, can you take over cpr? I started to do cpr on her for like a minute, two minutes. While he wen out there and got medication. Reporter: In court on tuesday, scheidt's attorney blames hospital administrators who gave him a badge for physician assistant, without checking credentials. Did you verify what mr. Scheidt had told you? I didn't. Why did you not verify? The office was very busy. Reporter: Scheidt's lawyer said he never lied and never intended to deceive anyone. And he told those who asked that he was a student. Prosecutors lined up a series of witnesses who said the teen intentionally played the part of a professional. You specifically saw mr. Scheidt, matthew scheidt, performing chest compressions? Yes. I had walked into the room and observed him with a stethoscope to a patient's chest, listening to breath sounds. And he had an i.V. Catheter in his hand. Reporter: And the prosecution will pick up with a long list of witnesses again today. Interestingly, once this trial wraps up, scheidt faces other charges for impersonating a police officer, evenllegedly pulling over a car. For that offense, josh, he can face up to an additional 22 years prison. The levels of life imitating art here, know no bounds. Let's turn to our sam

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